Phonograph-horn



J. J. STEFFAN.

PHONOGRAPH HORN.

APPLICATION FILED AUG-1|. 1919.

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PHONOGRAPH HORN.

APPLICATION FILED AUG-H, 1919.

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UNITED STATES JOSEPH J. STEFEL'N', 01 ST. LOUIS, MISSOURI.

PEONOGRLPE-EOBN.

Specification of Letters Patent. Patefltd Aug, 9 1921,

Application filed August 11, 1919. Serial Ro.'816,620.

To all whom it may concern:

Be it known that I, Josnrn J. STEFFAN, a citizen of the United States of America, a resident of the city of St. Louis, in the, State of Missouri, have invented certain new and useful Improvements in Phonograph- Horns, of which the following is a full, clear, and exact description, reference'ber ing had to the accompan ing. drawings, forming a part of this specification.

My invention relates to improvements in horns. The new horn is adapted for use on phonographs, and especially for talking machines of the cabinet type wherein the horn is inclosed by a cabinet on which the reproducer is mounted. The main object of the invention is to produce a simple and inexpensive horn having highly desirable acoustic properties. 1

With this object in view, the horn comprises wall members, preferably made of wood, and at least one of the wall members is secured under tension to the other wall members. a

In the preferred form of the invention, the top and bottom wall members are made of thin sheets of wood, known as veneer, and these thin sheets are tensioned and stretched onto the side wall members to which they may be cemented. By using thin wooden sheets in this manner, I rovide simple and inexpensive wall mem ers which may be easily bent to the contour of the horn, and by stretching these thin sheets and securing them under tension, I greatly im rove the acoustic properties of the horn.

owever, the thin wood or veneer, when delivered to the manufacturer, is not in the form of smooth flat sheets. It is usually distorted or warped so as to present irregular wavy surfaces at the top and bottom of the sheet. Furthermore, thin wood of this kind will split freely if it is not properly handled, and considerable difiiculty has been experienced in placin the thin sheets under tension without splittm the wood.

My object is to utilize these thin, inexpensive sheets as the main elements of a phonograph horn, and to place them under. approximately uniform tension throughout their lengths, at the same time stretching them onto other .wall members of the horn, without liability of splittin the thin wood. The tensioning and stretc ing eliminates constructed 1n a particular manner, as will be hereinafter fully pointed out. Briefly stated, the end margins of the thin sheet of wood are firmly secured in anchor members which extend entirely across the end port1ons of the sheet. 0 prevent any part of the thin wood from yielding in the anchor members, the latter are preferably cemented to the end margins of the wooden sheets, and while firmly anchored at their ends in this manner, the thin sheets are tensioned in a direction parallelwith the grain of the wood and at the same time stretched onto the side walls of the horn. Afterbeino' stretched in this manner, the tensioned sheets are preferably cemented to the side walls of the horn.

Fi re I is a perspective View of a phono grap horn constructed in accordance with this invention.

Fi II is a transverse section on theline II- I, I I.

Fig. II is a side elevation of the horn.

Fi IV is avertical section on the-line IV-+ V, Fig. III.

The phonograph horn I have shown to illustrate the invention comprises relatively thick side walls 1' having curved top and bottom edges, which converge toward one end of the horn. '2 and 3, respectively, designate the thin top and bottom walls of the horn,

each of said thinwalls preferably being a single sheet of thin wood stretched onto the side walls 1. Y 1

At the smallend of the horn, I secure an anchoring device A having an opening 4 for the admission of the sound waves, and provided with a slide 5 adapted to close saidopenin Grooves 6 are formed in the anchoring evice A to receive the narrow upper ends of the side walls 1, and similar grooves 7 are formed to receive the narrow end margins of the thin wall members 2 and 3. I The wall members are secured at the grooves 6 and by means of glue 8, which is indicated by shading in the Figs. II and III. It is im rtant to observe that'the thin wall mem rs 2 and 3 are thus firmly secured entirel across their narrow ends. Anchors 2 an 3', in the form of cleats or stretcher bars, may be secured by nails 9 to the top and bottom edges of the side walls 1. These anchors are grooved as shown at 10 (Fig. 1) to receive marginal portions of the side walls 1. One longitudinal edge of each anchor 2'--3' has a groove 12 extending throughout its length to receive the wide end margin of a thin wall members 2 or 3, and this end margin is cemented throughout its length to the grooved edge in which it is mounted. the cement being indicated by 13 in Figs. I and IV.

In assembling the elements of the horn, the end anchor A is glued to the side walls 1, and the end-margins of the thin sheets 2 and 3 are glued to the anchor A and also to the end anchors 2' and 3', respectively. Before the thin lower wall 3 is attached directly to the side walls 1, said thin wall is bent on the lower ed es of the side walls as suggested by dotted lines in Fig. 111, and the end anchor 3' is then firmly pulled in the direction indicated by an arrow (Fi III), so as to uniformly tension the thin sheet 3, at the same time stretching it onto the curved lower edges of the side walls. After the thin sheet has been firmly tensioned, the end anchor 3' lies in the position shown b full lines in Fig. III, and it may be quick y secured by means of the nails 9. Glue 14 is then applied to the adjacent longitudinal margins of the walls 1 and 2, so as to secure the tensioned wall 3 to the relative] firm side walls 1. Theglue is preferably applied only to the exterior o the horn.

To secure the thin up )er sheet 2, its end margins are first secure to the anchors A and 2', as previously pointed out, and said anchors are secured to the side walls 1, as shown in Fi s. I and III, while the thin, warped, wooden sheet 2 occupies the osition suggested by dotted lines in Fig. II The sheet 2 is then forced onto the adjacent curved edges of the wide walls 1. This operation tensions the sheet 2, stretching it to the contour of the upper edges of the side walls to which it is then secured by means of lue 15.

do not deem it necessary to show any of the mechanical devices for stretching the thin sheets 2 and 3. The ends of the anchors 2' and 3' are extended to receive a suitable stretching device, and any suitable pressure-exerting means may be employed to stretch the upper wall 2 onto the side walls.

By firmly anchoring the thin sheets entirely acrosstheir ends, I enable said sheets to be uniformly tensioned without liability of splittin the thin wood. The tensioning is in the direction of the grain of the wood, and while the thin sheets are held under tension their longitudinal margins are secured by the glue 14 and 16.

I claim:

1. A phonograph horn having side wall members, a wall member comprising a thin sheet of wood tensioned in the direction of the grain of the wood, the longitudinal margins of the tensioned wall member being secured to said side wall members, and means for anchoring the ends of said tensioned wall member.

2. A honograph horn having op ositely dispose elongated tensioned wal s, and means for anchoring the end margins of said tensioned walls.

3. A phonograph horn having thin top and bottom walls, relatively firm side walls having longitudinal edges onto which said thin top and bottom walls are tensioned, and end anchors to which the and margins of the thin tensioned walls are cemented, the longitudinal margins of said thin tensioned walls bein cemented to the longitudinal edges of said relatively firm side walls.

4. A horn comprising side walls members, relatively thin tensioned top and bottom wall members stretched onto said side wall members, and means for anchoring the ends of said tensioned wall members, the longitudinal margins of said tensioned wall mem- Ihers being secured to said side wall mem- 5. A phonograph horn having top and bottom walls comprising thin sheets of wood,'side walls havingcurved longitudinal edges onto which said top and bottom walls fllllfi bent and tensioned longitudinally of t a grain of the wood, and means for an-.

choring the ends of the thin sheets of tensioned wood forming said top and bottom walls, the longitudinal margins of said thin sheets of tensioned wood being cemented to said curved longitudinal margins of the side walls.

6. A phonograph horn having top and bottom walls com rising thin sheets of wood, and anchors aving recesses in which the end margins of said thin sheets of wood are cemented and securely held throughout the Ian ths of the respective and margins, and si e walls having longitudinal edges onto which said thin sheets of wood are ten sioned lon itudinally of the grain of the wood, the longitudinal margins of the thin sheets of wood being cemented to said side walls.

7 A honograph horn having side walls, end anc 1018 secured to the end portions of said side walls, and top and bottom walls comprising thin sheets of wood having their end margins secured to said and anchors, the lon itudinal mar ins of said thin sheets of wood being secure to said side walls.

8. A honograph horn having side walls provide with curved top and bottom edges,

end anchors secured to the, end portions of gins of said thin sheets of wood being cesaid side walls, said end anchors having remented to the longitudinal margins of said cesses extending from one side wall to the side walls. 10 other, and top and bottom walls comprising In testimony that I claim the foregoing I 5 thin sheets of wood having their end marhereunto aflix my signature.

gins arranged in said recesses and cemented to said end anchors, the longitudinal mar- JOSEPH J. STEFFAN. 

